This project explores the hypothesis that a calcium-activated neutral proteinase(s) (CANP) is associated with myelin and/or localized in axons and glial cells. This thesis has been developed from our demonstration of a calcium-mediated degradation of cytoskeletal as well as myelin proteins by a proteinase(s) present in spinal cord and brain white matter. Thus our detailed studies will be 1) to establish that CANP is associated with myelin: we plan to examine the enzyme (CANP) activity in different regions of brain, in myelin and subcellular fractions of brain during development and myelin from CNS and PNS of different species, and 2) to examine the localization of CANP by immunocytochemical technique after antisera is raised from purified CANP (which we have recently purified from bovine brain). The presence of this enzyme in myelin and related structures or cells may play a crucial role in the breakdown of myelin in demyelinating diseases (e.g. MS).